The Truth About Terpenes

[SamuiGrower]

Terpenes or “Terps” as they are colloquially called amongst us, are all the rage, if not the craze, amongst the stoner, grower and medical user community. We love to throw the word around but most don’t really know: what they are, or what they do.

 

Here’s the science of it. Or, at least enough of it as to not make you glaze over. 

 

What are Terpenes? They are medium chain (C10) hydrocarbons associated with many, many plants of which cannabis is just one. Citrus fruits, oily herbs/spices (thyme, sage, basil, rosemary, peppercorns, etc. are just a few examples of plants with terpenes. They are the main components of all essential oils. We are more familiar with them in our lives than we think. Camphene (camphor), Eucalyptol, Thymol, citronellol, pinene, etc. They are in mouthwash, tiger balm, insect spray, perfumes and food and beverages, to name just a few.

 

They are responsible for the aromas and flavors (organoleptic properties) of cannabis. It’s their association with cannabis that the conversation becomes contentious. More on this below.

 

They are produced in cannabis as a stress response to combat UV exposure (sunscreen), low humidity and insect/animal predation (herbivory). They are expressed and isolated in the trichomes of the plant. These are the sticky/resinous glands that look like tiny mushrooms (stalked capitate glandular trichomes). The modern practice in cannabis growing is to create controlled stress to increase terpene (and all secondary metabolites for that matter) production. Low humidity in the last few weeks of flowering (weeks 5-8) will increase trichome production as well as controlled drought stress and UV-B spectrum light (the science is still a bit unclear on this).

 

Here’s where the controversy begins. The word “Terpenes” is thrown around in the recreational cannabis world as a selling point, to convey how great the flower smells and tastes. Fair enough. In the medical cannabis world, the word is used in regards to its medicinal qualities and is usually paired with the phrase “Entourage Effect”. This is a re-manufactured term taken from “synergistic effect”.  One proven example of the entourage effect NOT involving terpenes is the relationship of THC with CBD. We know they act in tandem and the net result is better than the sum of the parts alone.  Simply stated, the hypothesis, and that’s all it is, is terpenes will enhance the effect of cannabinoids in a medical way, I.e. certain terpenes (in cannabis flower) will make you up, down, sleepy, calm, motivated, act as an anxiolytic (anti-anxiety), anti-emetic, etc. 

 

The entourage effect of terpenes in cannabis is purely hypothetical. There is no scientific or medical evidence that terpenes modulate the effect of cannabinoids on the endocannabinoid receptors in the body (CB1/CB2). In fact, there is more scientific evidence to state the contrary than to support it. When terpenes are isolated and studied (most are synthetically made and added, post production to distillates and extracts) they have medicinal qualities, i.e. Camphene acts as an anti-inflammatory and is a great transdermal for topical medications and Thymol is an anti-bacterial in mouthwash and limonene is an antioxidant. BUT, there is little evidence of the effects of smoking terpenes or the associative (synergistic) effect of cannabinoids and terpenes. It is purely hopeful supposition that terpenes are a ‘value added’ medicinal property of cannabis. Any associative effect is non-quantifiable and thus only hypothetical.

 

Aside from the natural terpenes that you smell and taste in cannabis flower (bud). The terpenes that are used in extracts, distillates, vapes, carts, etc. are all added post-processing, are synthetically made (it’s way to costly and inefficient to extract and isolate usable terpenes from flower) and are used mostly as a viscosity constituent and ‘flavoring’ in vaping. Live rosin is an exception. This is probably the best way to experience natural terpenes in smoking. Unfortunately, in short path distillation and SCE extraction, most of the natural terpenes are stripped out.

 

Want some more controversy? Terpene profiles are part of the genetic disposition of the cannabis strain (cultivar, soon to be replaced by the term chemovar). There is nothing a grower can do to change this profile other than providing controlled stress events, as stated previously, to increase the terpene response within the plant. We can not add different terpenes that did not originally exist in the strains DNA. To make it even more controversial, no two plants (of the same strain) will produce the same exact terpene profile. In fact, no two parts of the same plant will produce the same profile. Differences in lighting zones, irrigation, micro-climates and nutrition uptake will affect this as well.

 

The good part. Outdoor, soil grows show higher, more consistent terpene regularity than indoor CEA (controlled environment agriculture) plants.

 

So, there it is - a primer on terpenes. What say you? 

[stoner]

3 minutes ago, SamuiGrower said:

The good part. Outdoor, soil grows show higher, more consistent terpene regularity than indoor CEA (controlled environment agriculture) plants.

can't beat the sun. 

 

i would love to see a full glass greenhouse with cea done in thailand. the results would be something for the ages i think. 

[wombat]

4 hours ago, SamuiGrower said:

What say you? 

Genesis 1:29 makes things so much easier.

[Wuvu2]

17 hours ago, SamuiGrower said:

Low humidity in the last few weeks of flowering (weeks 5-8) will increase trichome production

One of the reasons we'll never see great outdoor bud produced in Thailand. I suspect cooling weather before harvest helps get a great finish as well.

 

I've noticed that the outdoors strains that rock in northern California weather are barely worth smoking when grown outdoors here. Genetics might help but I suspect we'll never see top notch outdoor weed grown in Thailand. Too bad. I much prefer great sun grown weed to anything indoors.

[SamuiGrower]

1 hour ago, Wuvu2 said:

I've noticed that the outdoors strains that rock in northern California weather are barely worth smoking when grown outdoors here

You’re correct but the limiting factor is not humidity it’s the light, surprisingly enough.

 

Equatorial strains all share the same trait: long finishing/maturing. 16 weeks flowering is not unusual at all. The cumulative light for a crop to mature and finish is called DLI (daily light integral). This is the intensity (measured in umol/ppfd) multiplied by time (hours) by square meter (canopy). Cannabis is a high DLI crop, perhaps the highest known. Cannabis needs around 50 DLI. There are 4 months in Thailand where the DLI is 40-45, the other 8 months, well below that (30-35). Since DLI, in relation to crop finishing (outdoors) is cumulative, finishing takes ‘forever’. When talking landrace strains, long finishing time is in the genetic coding (DNA). To be clear, when talking “landrace”, we mean  pure C. Sativa, not hybridized with C. Indica. 
 

 

Edited May 5, 2023 by SamuiGrower